In practice, it is known that, for example in the production of sausage-shaped products, like sausages, filling material is fed by a filling machine through a filling tube of a clipping machine into a tubular or bag-shaped packaging casing which is temporarily stored on the filling tube and which is closed at its front end, i.e. the end pointing in the feeding direction of the filling material, by a closure means, like a closure clip, or by fusing this end, respectively. The tubular packaging casing is pulled-off from the filling tube while being filled by the feeding pressure. At least during the filling process, a casing brake applies a frictional force to the tubular packaging casing while being pulled-off from the filling tube, in order to control the pull-off speed and to ensure an at least approximately constant filling degree. After a predetermined volume of filling material has been filled into said tubular packaging casing, gathering means with a first and a second displacer unit which can each be formed by a pair of reversibly moveable displacement elements, a plait-like portion of the tubular packaging casing is formed. The plait-like portion is at least approximately free of filling material. The clipping machine then places and closes at least one closure clip at the plait-like portion forming the rear end of the sausage or bag-shaped product, i.e. the end pointing opposite to the feeding direction by respective closing tools which are reversibly movable towards the plait-like portion.
From EP patent application 1 428 437, a clipping machine is known including a casing brake assembly. This known casing brake assembly is attached to a frame element of the clipping machine. The casing brake itself has a closed circular design and in particular a closed circular lip which completely surrounds the filling tube. A fork-shaped holding element including two rakes, accommodates and supports the casing brake in its operating position. For adjusting the force applied to the tubular casing, and for removing the casing brake from the clipping machine, the fork-shaped holding element with the casing brake halt therein, must be shifted along the filling tube in the filling direction. Thereafter, the casing brake may be removed out of the fork-shaped holder in a direction vertically to the longitudinal axis of the filling tube. A sensor arrangement may detect the presence or absence of the casing brake.
Moreover, EP patent application 1 748 696 discloses a clipping machine for sausages, which includes a fork-shaped holder for a casing brake. The holder has a semicircular portion formed by two arms. The casing brake of a generally circular shape has a circumferentially extending groove into which the arms of the fork-shaped holder engage for securing the casing brake in axial direction on the clipping machine. An inductive sensor is provided, which may detect a metallic component of the casing brake when in its operating position.
Even if sensor means which detect the presence or absence of a casing brake may prevent an operation of the clipping machine without a casing brake assembly being in its operating position in order to avoid the possibility that an operator can reach into the gathering means and can thus be hurt seriously, during operation of a clipping machine, there exists still the risk that an operator may grasp into moving parts of said clipping machine, like the gathering means, e.g. by entering a gap between a housing portion of the clipping machine accommodating the gathering means, and the casing brake positioned upstream said gathering means outside the housing.
In some cases where the casing brake has to be shifted along the filling tube, in particular in a direction away from the gathering means, e.g. for adjusting the frictional force applied to the casing material or for adapting the clipping machine to different products, the size of the gap between the gathering means and the casing brake may disadvantageously be increased, thereby increasing the risk of reaching the gathering means with the fingers of an operator.
Thus, it is an object of the present invention to provide a casing brake assembly and a clipping machine using the casing brake assembly which overcome the above mentioned drawbacks and which allows a simplified and compact design of the clipping machine with a high level of security for the operator.